Stable affixation system for guided dental implantation

ABSTRACT

A stable affixation system for dental implantation includes a fixation tray having, for rapid placement, a housing defining a chamber whose inner surface is configured to house a flowable or malleable material (configured to harden) and be placed over one or more teeth during guided dental implantation surgery. A mechanism for urging the material against the teeth may comprise side walls having an inwardly directed extra flexible arm extension or an inwardly directed step. A lock mechanism may comprise a wedge positioned over the fixation tray to reduce or eliminate freedom of movement of the tray. For rapid removal, the system may include mechanisms (for example an element rotating inside the tray) for applying force on the tray and material and for ensuring that the material adheres more strongly to the tray than to the teeth. The system is sturdy enough to withstand forces including from various angles and leverage.

FIELD AND BACKGROUND OF THE INVENTION

The invention relates to affixation systems and more particularly toaffixation systems for guided dental implantation surgery including afixation tray configured to house a hardening material and including alock.

Dental implants are used in cases where natural teeth are missing orhave to be extracted. Dental implantation surgery involves drilling ahole and enlarging it to a specific size in the maxilla or mandible(upper or lower jaw bone) and then screwing in an implant, a screw-likeobject into the jaw. After the implant surgery, an abutment and crownare then placed.

The correct and accurate placement of the implant is very important forvarious reasons. There are anatomical structures which one does not wantto drill into such as the inferior alveolar and mental nerves, maxillarysinuses or perforating bone. In addition, one does not want to drillinto a tooth root or another implant. It is not easy to accuratelyposition the implant “blindly” (only seeing the original access opening)around 8-13 mm deep into bone. Ideally, implants should be placed in aposition and orientation so as to have biting forces in the long axis ofthe tooth. Improper placement might prevent achieving this Implantsshould be placed so as to leave a minimum of 2 mm of bone to preventbone resorption. There is also an aesthetic component for the placementof implants especially in the anterior of the mouth, where the finalaesthetic result is affected by the precise placement of the implant.

Originally, the only way to perform any surgery in general was freehand,without any guidance relating to the anatomical structures which one mayencounter during surgery. In order to compensate for this, surgicalaccess openings had to be large enough to allow visual verification.Laparoscopy as well as other guides has helped with this aspect in manytypes of surgeries.

In dentistry, utilizing guided dental surgery helps the surgeon followthe preplanned treatment plan. It makes the surgery minimally invasive,which reduces the risk of tissue damage and facilitates achieving theprecision needed. Guided surgery is therefore a preferred approach fordental implant surgery.

During dental and certain other kinds of guided surgery there is a needfor real-time computerized measurement of spatial position andorientation of specially marked objects, such as surgical instrumentsand implants to be implanted in pre-planned positions. The orientationand location of the surgical instruments is monitored by positionsensors and the real-time location of the instruments can be displayedon previously acquired patient image data. The orientation and locationof the patient is also typically tracked separately, to allow forsensing of anatomy movement relative to the tracked instruments duringthe operation. In dental surgery and in certain other surgeries, thevarious orientations and locations of the tracked objects need to bedetermined with great precision—in the case of dental surgery typicallywithin an accuracy of less than a quarter of a millimeter.

SUMMARY OF THE INVENTION

One aspect of the invention is a stable affixation system for guideddental implantation, comprising a fixation tray customizable to thepatient including a housing that defines a chamber configured to house aflowable or malleable material and be placed over one or a plurality ofteeth of a person during the guided dental implantation surgery, thehousing having sides, at least a portion of the sides are configured toflex under stress, the sides configured to urge the flowable ormalleable material against the teeth; and a lock positioned on thefixation tray so as to reduce or eliminate a freedom of movement of thefixation tray.

In certain embodiments, the lock is a locking wedge positioned over thefixation tray. In certain embodiments, the locking wedge has an innersurface configured to define a chamber into which the fixation tray isconfigured to fit either snugly or using a friction fit.

In certain embodiments, the lock includes a mechanism for fixating atleast side portions of the housing rigidly in place.

In certain embodiments, the housing includes a structure configured tojoin the flowable or malleable material, once hardened, to the housingsuch that a greater separation force is required to separate theflowable or malleable material, once hardened, from the housing, than aseparation force required to separate the flowable or malleable materialfrom the one or the plurality of teeth.

In certain embodiments, the lock is configured to reduce a freedom ofmotion of each a first side wall and of a second side wall of thefixation tray.

In certain embodiments, the housing comprises a pair of inclined,inwardly directed arm extensions that extend from an inner surface ofthe chamber. In certain embodiments, the housing is made from a firstmaterial and the arm extensions are made of a second material that isflexible.

In certain embodiments, the lock includes a first locking wedge sidewall thicker than a flexible first side wall of the housing and a secondlocking wedge side wall thicker than a flexible second side wall of thehousing.

In certain embodiments, the fixation tray has recesses and the lock hascorresponding projecting members. In certain embodiments, the projectingmembers project from an underside of a locking wedge top portion of thelock. In certain embodiments, the recesses are planar recesses situatedsuch that when the projecting members mate with the planar recesses, afirst planar projecting member adjacent to and inward of a first sidewall of the fixation tray and a second planar projecting member adjacentto and inward of a second side wall of the fixation tray.

In certain embodiments, the housing has an elongated cavity configuredto receive a tracking element.

In certain embodiments, an end view of at least one of (i) the fixationtray or (ii) the lock is substantially U-shaped.

In certain embodiments, the housing includes arm extensions that areeach configured to urge the flowable or malleable material to harden inan undercut of the one or the plurality of teeth to stabilize thesystem.

In certain embodiments, the fixation tray includes side walls and eachof the arm extensions is more flexible than each of the side walls.

In certain embodiments, the housing has spaces configured to allow theflowable or malleable material to flow into and, once hardened, to lockinto.

Another aspect of the invention is a method of using a stable affixationsystem during dental implantation, comprising deploying a fixation trayholding a flowable or malleable material over one or a plurality ofteeth, the fixation tray having a housing defining a chamber configuredto house the material and having sides at least a portion of which areconfigured to flex under stress, the sides configured to urge theflowable or malleable material against the one or the plurality ofteeth; deploying a lock over the fixation tray, the lock configured toreduce or eliminate a freedom of movement of the fixation tray; allowingthe flowable or malleable material to harden into a rigid but breakablestate; removing the lock and then removing the fixation tray by exertinga force on the fixation tray to generate stress that breaks at least aportion of the hardened material.

In certain embodiments, exerting the force involves rotating an elementin a cavity of the housing thereby breaking at least a portion of thehardened, previously flowable or malleable, material and allowing the ata portion of the sides of the housing to flex.

In certain embodiments, the method further comprises performing theguided dental surgery while the tray and lock remain in place in asturdy and stable position.

In certain embodiments, the method further comprises rigidly attaching aconnector to the tray and either (a) performing a computer tomographyscan of the one or plurality of teeth before deployment of the fixationtray and before deployment of the lock and then after deployment of thetray and lock moving a tracking device along the one or a plurality ofteeth to register the one or a plurality of teeth, or (b) performing acomputer tomography scan of the one or plurality of teeth afterdeployment of the fixation tray and lock and a connector rigidlyattached to the fixation tray then either (i) moving a tracking devicealong the connector to register the connector or (ii) rigidly attachinga tracking device to the connector to register the connector based on aphysical relationship between the tracking device and the connector.

A still further aspect of the invention is a stable affixation systemfor guided dental implantation, comprising a fixation tray having ahousing that defines a chamber configured to house a flowable ormalleable material and be placed over one or a plurality of teeth of aperson during the guided dental implantation surgery, the flowable ormalleable material configured to harden into a crisp or brittle materialso as to conform to a contour of the one or the plurality of teeth, thehousing having a mechanism configured to urge the flowable or malleablematerial toward the one or the plurality of teeth; and a locking wedgepositioned over the fixation tray so as to reduce or eliminate a freedomof movement of the fixation tray.

In certain embodiments, the housing includes a mechanism configured tojoin the flowable or malleable material, once hardened, to the housingsuch that a greater separation force is required to separate theflowable or malleable material, once hardened, from the housing, than aseparation force required to separate the flowable or malleable materialfrom the one or the plurality of teeth.

In certain embodiments, the housing has a mechanism configured to holdat least part of a tracking element and a mechanism configured to exertstress on the housing and/or on the crisp or brittle material so as tobreak at least a portion of the crisp or brittle material and dislodgethe fixation tray from the one or the plurality of teeth.

A yet still further aspect of the invention is a stable affixationsystem for guided dental implantation, comprising a fixation traycustomizable to the patient including a housing that defines a chamberconfigured to house a flowable or malleable material and be placed overone or a plurality of teeth of a person during the guided dentalimplantation surgery, the housing having sides, at least a portion ofthe sides are configured to flex under stress, the sides configured tourge the flowable or malleable material against the teeth, wherein thehousing includes a locking mechanism configured to reduce or eliminate afreedom of movement of the fixation tray by reducing or eliminating anability of the at least the portion of the sides of the housing to flexunder stress.

In certain embodiments, the least a portion of the sides of the housingare configured to flex such that a further a portion of the sides isfrom a top portion of housing the more that portion of the sides spreadsoutward under stress.

In certain embodiments, the system further comprises a registrationelement configured to be rigidly attached to the tray.

These and other features, aspects and advantages of the invention willbecome better understood with reference to the following drawings,descriptions and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments are herein described, by way of example only, withreference to the accompanying drawings, wherein:

FIG. 1 is an exploded view of a stable affixation system for dentalimplantation together with a pole with a connector to a patient trackingdevice, in accordance with an embodiment of the invention;

FIG. 2 is an assembled version of the stable affixation system of FIG. 1together with the tracking device, in accordance with an embodiment ofthe invention;

FIG. 3A is a view of a first of the arm extensions of the fixation trayof the stable affixation system from a side and an end, in accordancewith an embodiment of the invention;

FIG. 3B is a view of a second of the arm extensions of the fixation trayof the stable affixation system from a side, in accordance with anembodiment of the invention;

FIG. 4 is an end view of a fixation tray of the stable affixationsystem, in accordance with an embodiment of the invention;

FIG. 5 is a top view of a fixation tray of the stable affixation system,in accordance with an embodiment of the invention;

FIG. 6 is a side view of a fixation tray of the stable affixationsystem, in accordance with an embodiment of the invention;

FIG. 7 is a bottom view of a fixation tray of the stable affixationsystem, in accordance with an embodiment of the invention;

FIG. 8 is an end view of a locking wedge of the stable affixationsystem, in accordance with an embodiment of the invention;

FIG. 9 is a top view of a locking wedge of the stable affixation system,in accordance with an embodiment of the invention;

FIG. 10 is a side view of a locking wedge of the stable affixationsystem, in accordance with an embodiment of the invention;

FIG. 11 is a bottom view of a locking wedge of the stable affixationsystem, in accordance with an embodiment of the invention;

FIG. 12 is a side view of a pole of or used with the stable affixationsystem, in accordance with an embodiment of the invention;

FIG. 13 is a sectional view of the pole of FIG. 12 of or used with thestable affixation system, in accordance with an embodiment of theinvention;

FIG. 14A is a side view of a tracking device and handle for the stableaffixation system, in accordance with an embodiment of the invention;

FIG. 14B is a front view of a tracking device and handle for the stableaffixation system, in accordance with an embodiment of the invention;

FIG. 14C is a further view of the tracking device and handle of FIGS.14A-Fig. B;

FIG. 15 is an end view of one version of a fixation tray of the stableaffixation system, in accordance with an embodiment of the invention;

FIG. 16 is a flow chart of a method, in accordance with an embodiment ofthe invention; and

FIG. 17 is a flow chart of a method, in accordance with an embodiment ofthe invention;

FIG. 18 is a flow chart of a method, in accordance with an embodiment ofthe invention;

FIG. 19 is a schematic of a lock mechanism applied to FIG. 4, inaccordance with an embodiment of the invention;

FIG. 20 is a schematic of another lock mechanism applied to FIG. 4, inaccordance with an embodiment of the invention;

FIG. 21 is a flow chart of a method, in accordance with an embodiment ofthe invention;

FIG. 22 is a flow chart of a registration method, in accordance with anembodiment of the invention; and

FIG. 23 is a flow chart of another registration method, in accordancewith an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplatedmodes of carrying out the invention. The description is not to be takenin a limiting sense, but is made merely for the purpose of illustratingthe general principles of the invention, since the scope of theinvention is best defined by the appended claims.

The invention generally provides a stable affixation system for guideddental implantation, comprising in certain embodiments a fixation trayand a lock. In certain embodiments, the system is designed to be able toattach a tracking device that interacts with a guided dentalimplantation surgery system wherein such tracking device is keptimmobile or at least immobile relative to the patient's mouth.

Certain embodiments of the invention utilize several principles thatreflect advantages or requirements for affixation of tracking systemsused during dynamic guided dental implant surgery. The first principleis fast and easy placement of a system that is customizable to thepatient. The system should allow attachment of a tracker at ananatomical part of the subject such that the tracker and the anatomicalpart only move in exact conjunction with the surgical site. The secondprinciple is stability of the system holding the tracker even in theface of significant force applied (against the tracker or its connectoror against the system directly) including from a variety of angles andthrough leverage. The third principle is rapid removal of the systemwith limited force without damaging the teeth.

In certain embodiments, the principle of fast and easy placement isaccomplished by a number of things including a fixation tray housing anda flowable or malleable material placed inside the housing which iseffectively customizable to the particular patient's teeth because ofthe material being flowable or malleable. The second principle ofstability is in certain embodiments accomplished by several thingsincluding the hardening of the flowable or malleable material, a lockmechanism (derived from features of the lock and features of the tray)which reduces or eliminates the freedom of movement of the tray and amechanism to urge the material against the one or a plurality of teeth.The third principle of fast removal with limited force and withoutdamaging the teeth is accomplished in certain embodiments by a number ofthings including: an easily removed lock mechanism; using a flowable ormalleable material that hardens into a crisp or brittle material andproviding the material inside a tray configured to break easily fromforces or stress such as shear stress; a mechanism for generating forcesor stress (such as shear stress) on the tray and on the material insidethe tray; providing that the separation force needed to separate thematerial from the tray is greater than the separation force needed toseparate the already hardened material from the teeth so that thematerial is removed with the tray and does not stay attached to theteeth when the tray is removed; and using a tray whose housing has atleast a portion or portions or areas or points configured to flex understress (in some embodiments this flexing leads to breakage also of thetray under this stress).

The fixation tray may have a housing that defines a chamber whose innersurface is configured to house a material that is a flowable ormalleable material so that the housing in effect becomes customizable tothe individual patient's teeth. The feature of the housing havingportions that flex under stress facilitates dislodging of the fixationtray.

In one implementation of the housing of fixation tray, the fixation traymay have side walls and a fixation tray top portion that may connect afirst side wall with a second side wall of the fixation tray. In certainembodiments, these side walls or portions thereof are configured to flexat least to some extent under stress or pressure. In some cases, theseside walls have arm extensions that are significantly more flexible thanany other part of the fixation tray including than the first and secondside walls, for example because in some embodiments the arm extensionsare made of a different material, in one non-limiting example silicone,than the side walls themselves. The extra flexibility of the armextensions in some embodiments is due to manufacturing considerationsbut the arm extensions help urge the flowable or malleable materialhoused by the fixation tray inwardly toward the teeth and may render thefixation tray adaptable to fit more jaw and teeth sizes. This extraflexibility also makes manufacturing the fixation tray easier in certainembodiments. In other cases, the side walls of the fixation tray have aninwardly-directed pair of steps at or near a free end of the side wallsor at another position along the side walls.

The affixation system also includes a lock which in certain embodimentsis implemented as a locking wedge configured to be placed on thefixation tray in order to reduce or eliminate the freedom of movement ofthe fixation tray that would otherwise occur from forces on the tray (orfrom forces on the tracking device (not shown) or the connector of thetracking device that in turn exerts force on the tray) while the tray ispositioned on the teeth during the guided dental implantation surgery.

After the flowable or malleable material hardens into a rigid state in acrisp form, one may rapidly remove the affixation system by for exampleremoving the locking wedge followed by exerting a force in the tray suchas a force on an element situated in a cavity of the housing (forexample a pole that can be rotated within the cavity). The force may beexerted on the element to generate forces or pressure or stress such asshear stress to break at least a portion of the hardened material forexample on an occlusal surface of the plurality of teeth and to causethe all or a portion of the sides of the housing (including any armextensions or steps) to flex so that the fixation tray can be dislodgedand removed from the one or the plurality of teeth. If a step is usedinstead of extra flexible arm extensions, the whole first and secondside wall or the sides or side portions of the housing together with thestep would flex somewhat due in one example to recesses alongside theside walls or side portions of the housing.

In certain embodiments, the affixation system is configured to berapidly placed on the one or plurality of teeth, is configured to berapidly removed from the one or plurality of teeth and/or is configuredto be maintained in position in a stable and secure manner (due in partto the locking mechanism) in the face of significant weight or forceapplied at any of a variety angles including such force applied throughleverage.

The principles and operation of a Stable Affixation System for GuidedDental Implantation may be better understood with reference to thedrawings and the accompanying description.

As shown in FIGS. 1-15, especially FIGS. 1-2, 4-5 and 8, one embodimentof the invention is a stable affixation system 10 for guided dentalimplantation that comprises a fixation tray 20 that in certainembodiments has a housing 20 a that defines a chamber 25 configured tohouse a flowable or malleable material (not shown) and be placed overone or a plurality of teeth of a person during guided dentalimplantation surgery. The use of the flowable or malleable material thathardens so as to conform to the shape of the tooth or teeth of thepatient facilitates customizing system 10 (and in particular the housing20 a of tray 20) for the individual patient. This facilitates rapidpositioning of system 10 on the one or more teeth of the patient.

The mechanism for rapid positioning of system 10 onto the individualpatient's teeth may also be implemented at least in part by providinghousing 20 a with a mechanism for urging the flowable or malleablematerial against the one or the plurality of teeth. Accordingly, incertain embodiments, housing 20 a may have a pair of inwardly directedarm extensions 32, 34 (FIGS. 1-3B) or a pair of inwardly directed steps23 a, 23 b (FIG. 15) that extend from an inner surface 25 a of chamber25, each arm extension 32, 34 or step 23 a, 23 b of the pair configuredto urge the flowable or malleable material against the one or moreteeth.

Although FIG. 4 depicts housing 20 a (and in particular inner surface 25a of chamber 25 defined therein) to include straight portions of itswalls, this is only one non-limited implementation and in otherembodiments housing and in particular inner surface 25 a of the chamber25 can have round or curved walls or borders. Housing 20 a definingchamber 25 may include side portions that may be rounded or straight ora combination of the two. In one implementation, housing 20 a (as wellas chamber 25) includes a first side wall 22, a second side wall 24 anda fixation tray top portion 26 that connects the two side walls 22, 24.Side walls 22, 24 may be straight or curved or a combination. In oneversion shown in FIG. 4, housing 20 a comprises substantially side walls22, 24 that have straight portions and rounded portions excluding anyarm extensions 32, 34 or steps 23 a, 24 b.

In certain embodiments, the purpose of fixation system 10 is to be ableto attach a tracking system that does not move—or at least does not moverelative to the patient's mouth—during the guided dental implantationsurgery. To this end, in one non-limiting implementation, fixation tray20 may have a portion such as a top portion 26 of housing 20 a (forexample including a holder 28 which is an area of top portion 26) thatdefines within it (i.e. within holder 28) a cavity, for example anelongated cavity 62, configured to receive a tracking device (not shown)or a handle and/or a connector 60 that connect to such a trackingdevice. The tracking device may be used during dental implantationsurgery. Connector 60 may in some embodiments be made of titanium andmay also connect to a registration device or connector 60 itself may bea registration device or part of one. In the embodiment shown in FIG. 1and FIG. 2, connector 60 connects to tray 20 using pole 65 situated at afirst end of connector 60 and connects to the tracking device at theother end of connector. It should be understood that the pole 65 is anon-limiting example of how connector 65 can connect to tray 20 and manyother examples are possible with components of other shapes. Inaddition, the term “pole” is not intended to suggest being cylindricalalthough it can be.

When lock 40 or locking wedge 40 is not deployed onto fixation tray 20,at least a portion of housing 20 a such as side walls 22, 24 areconfigured to flex under stress. In some embodiments, housing 20 a mayalso be configured to flex under stress at least to some extent from thefact that it defines an open chamber (until the flowable or malleablematerial hardens into a rigid state). One further way of renderingportions of housing 20 a (for example side walls 22, 24) able to flexunder stress is to incorporate at least one recess for example at leastone recess in the wall of the housing 20 a such as recess 27 alongsidefirst side wall 22 and recess 29 alongside second side wall 24. Recesses27, 29, in one non-limiting embodiment are planar recesses between therespective side wall and a portion of top portion 26, for example holder28. Other configurations of recesses are also possible in which recesses27, 29 are not planar. Other ways of making portions of housing 20 aconfigured to flex under stress are also contemplated such as from thenature of the material that housing 20 a is made from. In some versionshousing 20 a is cylindrical thereby requiring only a single recess.

In certain embodiments, portions of housing 20 a, for example side walls22, 24 are configured to flex under stress such that free ends 22 b, 24b of walls 22, 24 spread outward, or at least spread outward more thanportions of housing 20 a closer to top portion 26. This could occur, forexample, as a result of a clamping motion at the other ends of the sidewalls 22, 24 caused by lock 40 or locking wedge 40.

In versions where housing 20 a includes a fixation tray top portion 26configured to connect first and second side walls 22, 24, then the innersurface 25 a of chamber 25 may be defined by an inner surface of traytop portion 26 together with an inner wall surface 22 a, 24 a of each ofthe first and second side walls 22, 24. Chamber 25 is configured tohouse the flowable or malleable material (not shown) which as part oftray 20 may be placed over one or a plurality of teeth (not shown) of aperson during guided dental implantation surgery.

In one embodiment, first side wall 22 and the second side wall 24 areeach made of a first material and each side wall 22, 24 has an armextension 32, 34 that is more flexible than side wall 22, 24. Armextensions 32, 34 may be configured to urge the flowable or malleablematerial against the one or the plurality of teeth.

The flowable or malleable material, in some embodiments, is of the typeof material used for temporary crowns. In one non-limiting example, theflowable or malleable material is highly viscous akin to the viscosityof ketchup (5000-20000 mPa·s at 25° C.) or peanut butter (10⁴ to 10⁶mPa·s) or even pitch (2.3×10¹¹) and in another example has low viscosityakin to that of whole milk (2.2 mPa·s at 20° C.) or even akin toanything with more viscosity than water (1 at 20° C.) or anything inbetween any of these ranges. In any event, the flowable or malleablematerial is not only configured to harden but is also configured toharden into a crisp or brittle material that may be easily breakable inresponse to the stress, especially in response to shear stress, sincethis is necessary when one wants to dislodge the fixation tray 20 fromthe one or plurality of teeth.

In one embodiment, arm extensions 32, 34 extend from each side ofhousing 20 a, for example by extending from each of side walls 22, 24 ofhousing. In one implementation, arm extensions 32, 34 extend from a freeend of side walls 22, 24 respectively (i.e. arm extension 32 extend froma free end of side wall 22 and arm extension 34 extending from a freeend of side wall 24). In another embodiment, arm extensions 32, 34extend from a point adjacent the free end of side walls 22, 24respectively. In other embodiments, arm extensions 22, 24 extend from apoint a few millimeters (1 or 2 or 3 mms) above the free end of sidewalls 22, 24. In some embodiments, arm extensions extend from a midpointor a different portion of each of side walls 32, 34. In certainembodiments shown in FIGS. 1-2, arm extensions 32, 34 are inwardlydirected. In certain embodiments, arm extensions 32, 34 are alsoinclined, in one non-limiting example inclined at an angle between 30°and 60° (for example between) 40°-50° relative to side walls 22, 24respectively (or relative to sides of housing 20 a or sides of innersurface 25 a of chamber 25). The free ends 22 b, 24 b, of side walls 22,24 refer to the end furthest from top portion 26 that in someembodiments connects the side walls 22, 24.

Arm extensions 32, 34 may be made of a material different from the restof fixation tray 20, for example different from housing 20 a ordifferent from side portions of housing 20 a or different from theremainder of each side wall 22, 32. For example, in one embodiment armextensions 32, 34 are made of silicone and the silicone is flexible (andmore flexible than any other part of the fixation tray 20 or housing 20a. The fact that arm extensions 32, 34 are inwardly directed and in somecase also inclined helps push or urge the flowable or malleable materialtoward the one or more teeth and helps the fixation tray 20 fit more jawand teeth sizes. Arm extensions 32, 34 are each configured to formalongside an undercut of the one or more teeth and urge the flowable ormalleable material to adhere closely to the anatomical formation of theone or more teeth and into the undercuts so that when this materialhardens into a rigid state it in effect grips the one or the pluralityof teeth at the undercut of the one or the plurality of teeth. Thisincreases the stability of system 10 in that the entire system 10 notonly cannot be dislodged as a unit but in fact is substantially immobileduring the dental surgery.

As a result, there is no realistic option to pull the tray 20 plushardened material straight vertically up off the teeth.

By using a tray 20 having at least portions or a portion that isconfigured to flex under stress, and by using a flowable or malleablematerial that once hardens is crisp or brittle, the hardened material inchamber 25 breaks when pressure is exerted (for example by rotating anelement, such as pole 65 of connector 60, in cavity 62 of top portion 26of tray 20) because the force from rotating element 65 generatespressure or stress against fixation tray 20 that translates into stress(such as shear stress) or pressure against the hardened material whichbreaks it and makes it break away from the teeth (since the hardenedmaterial is strongly attached to tray 20). Thus, the hardened materialcomes off with the tray 20 when the fixation tray 20 is dislodged. Ifthe tray were rigid and not configured to flex under stress, the stressexerted against the tray would not cause the hardened material to breakand exerting a force on tray 20 would pressure the tooth or teeththemselves and may simply break or take out the whole tooth or teeth.

In certain embodiments, the housing includes a mechanism or structureconfigured to join the flowable or malleable material, once hardened, tothe housing such that a greater separation force is required to separatethe flowable or malleable material, once hardened, from the housing,than a separation force required to separate the flowable or malleablematerial from the one or the plurality of teeth. In one non-limitingimplementation of this mechanism or structure, fixation tray 20, and inparticular housing 20 a, may have holes 21 (FIG. 1) (or spaces thatassume other shapes such as elongated or otherwise) configured to allowthe flowable or malleable material to flow into, and when hardened lockinto. This way, when the fixation tray 20 is dislodged, the hardenedmaterial (formerly flowable or malleable material) breaks with it anddislodges from the teeth. This facilitates rapid removal of the systemwith limited force and without damaging the teeth. Although FIG. 1depicts one non-limiting implementation in which one or more holes 21are situated in side walls 22, 24 of housing 20 a of fixation tray 20,it is contemplated that in other implementations, the one or more holes21 or spaces of other shapes may be situated in other portions offixation tray 20 such as the top portion 26 of fixation tray. In anothernon-limiting implementation of this mechanism, the flowable or malleablematerial is configured by the type and nature of the material itself toadhere to a stronger degree to the material from which the housing oftray 20 is made than the degree to which the flowable or malleablematerial (once hardened) adheres to the one or the plurality of teeth.

Note that as seen in FIG. 1, tray 20 is upside down relative to how itwould be placed on a patient's lower tooth or teeth and right side up interms of how it would be placed on a patient's upper tooth or teeth.Hence, for convenience, the phrase “placed over” or “deployed over” or“placed on” or “positioned on” one or a plurality of teeth as used inthis patent application should be understood broadly to describe bothplacing, deploying or positioning the tray 20 over a patient's lowerteeth (or tooth) as well as placing, deploying or positioning oraffixing tray 20 under the patient's upper teeth. Likewise, in thispatent application when it is stated that the lock 40 or locking wedge40 is placed or deployed “over” or “on” tray 20, the word “over” and theword “on” in this context should be understood broadly to also encompassscenarios where the system is applied to upper teeth and the lock 40 orwedge 40 is affixed to the tray 20 by placing lock 40 or wedge 40 undertray 20 when the tray 20 is held in a position secured to (or inposition to be secured to) the upper teeth.

As seen from FIGS. 1-2 and 8-11, fixation system 10 may also comprise alock 40 positioned on tray 20 (which may be implemented in oneembodiment as a locking wedge 40 positioned on or over the fixation tray20) so as to reduce or eliminate a freedom of motion or movement ofhousing 20 a or of all or part of side portions of housing 20 a or ofsides or of first and second side walls 22, 24 of housing 20 a offixation tray 20. Lock 40 or Locking wedge 40 is configured with somemechanism designed to fixate housing 20 a or at least side portions ofhousing 20 a rigidly in place. In one implementation, lock 40 or lockingwedge 40 is configured to fixate side walls 22, 24 rigidly in place.

In certain embodiments of locking wedge 40, locking wedge 40 has aninner surface 40 a (FIG. 8) configured to define a chamber 45 into whichthe fixation tray 20 is configured to be emplaced or to be fit. Forexample, inner surface 40 a may be configured such that tray 20 forexample fits into chamber 45 snugly or for example fits into chamber 45using a friction fit or under pressure.

In one non-limiting implementation of the mechanism to fixate or removethe flexibility of the housing 20 a or of at least of a portion ofhousing 20 a, locking wedge 40 may include a first locking wedge sidewall 42 thicker than the first side wall 22, a second locking wedge sidewall 44 thicker than the second side wall 24 and may also include alocking wedge top portion 46 configured to connect the first and secondlocking wedge side walls 42, 44. FIG. 9 is a top view that depicts sides44, 46 of wedge 40 as if splayed outward but this view is not intendedas a realistic depiction.

As noted and as seen from FIG. 4, fixation tray 20 or its top portion 26may in certain embodiments have a recess 27 situated alongside side wall22 for example alongside a protruding top portion of first side wall 22and a recess 29 situated alongside side wall 24 for example alongside aprotruding top portion of second side wall 24. FIG. 4 does not show andis not intended to depict any arm extensions 32, 34 or any steps 23 a,23 b that housing 20 a may have.

As seen from FIG. 8, locking wedge top portion 46 in certain embodimentshas projecting members 47, 49 that are configured to mate with or fitinside at least a portion of recesses 27, 29 respectively, as seen alsofrom FIG. 1. For example, locking wedge top portion 46 may have planarprojecting members 47, 49 that correspond to planar recesses 27, 29 incertain embodiments. In other embodiments, recesses 27, 29 fit togetherwith projecting members 47, 49 without either of them being planar.Projecting members 47, 49, which may be planar, may project from anunderside of the locking wedge top portion 46.

As seen from FIGS. 1-2, 4 and 8, in one embodiment, planar recesses 27,29 are situated such that when the planar projecting members 47, 49 matewith the planar recesses 27, 29, a first planar projecting member 47 isadjacent to and inward of the first side wall 22 of the fixation tray 20and a second planar projecting member 49 is adjacent to and inward ofthe second side wall 24 of the fixation tray 20.

In certain embodiments of system 10, there is a structural means ofsnapping or locking or fitting together by friction fit or otherwisefixedly connecting locking wedge 40 to fixation tray 20. In onenon-limiting implementation of this connection shown in FIG. 1, FIG. 5and FIG. 11, both fixation tray 20 and locking wedge 40 have ridges 99on portions of their side walls. For example, as shown in FIGS. 1, 5,11, outer surfaces of side walls 22, 24 of fixation tray 20 and innersurfaces of side walls 42, 46 of wedge 40 have corresponding or matchingridges 99.

When locking wedge 40 is placed on fixation tray 20, locking wedge 40 isconfigured to reduce or eliminate a freedom of movement of each of thefirst side wall 22 and the second side wall 24 of fixation tray 20. Inone non-limiting example, locking wedge 40 is configured to reduce afreedom of movement of each of the first side wall 22 and the secondside wall 24 by 40% (or by at least 40%) or in other embodiments by 50%(or by at least 50%) or in other embodiments by 70% (or by at least 70%)or in still other embodiments by 90% (or by at least 90%) or in stillother embodiments by a particular percent between 40% and 95%.

As can be seen from FIG. 4 and FIG. 8 an end view of at least one of (i)the fixation tray 20 or (ii) the locking wedge 40 is substantiallyU-shaped. Although FIG. 4 does not include arm extensions 32, 34, evenwith arm extensions 32, 34 (see FIG. 2) tray 20 may be consideredsubstantially U-shaped.

In another implementation of lock 40 shown in FIG. 19 and FIG. 20, thehousing 20 a includes locking mechanism 40 configured to reduce oreliminate a freedom of movement of the fixation tray 20 by reducing oreliminating an ability of the at least the portion of the sides of thehousing to flex under stress. In one non-limiting example, lock 40comprises a clamp 41 a and/or a fastener 41 b (i.e. screw 41 b or a pairof screws 41 b) integrated with the tray 20 (or in other versions notintegrated with the tray 20) such that adjustment of the clamp 41 aand/or screw(s) 41 b is configured to reduces or eliminates the abilityof housing 20 a to flex under stress. In one implementation of thisexample, the clamp 41 a and/or screw(s) 41 b is configured to accomplishthis by locking side walls 22, 24 of housing 20 a, for example bytraversing recesses 27, 29. Another implementation of lock 40 is similarto FIG. 20 except that there are no recesses 27, 29 in tray 20 and theclamp 41 a is positioned to grip tray 20 further down, that is furtherfrom top portion 26 and close to free ends of side walls 22, 24 (or atleast closer to free ends of side walls 22, 24 than shown in FIG. 20).In that case, lock 40 may also comprise screw(s) 41 a (although in otherversions clamp 41 a operates without screws 41 b).

Accordingly, one particular embodiment of the invention is a stableaffixation system 10 for guided dental implantation, comprising afixation tray 20 customizable to the patient including a housing 20 athat defines a chamber 25 configured to house a flowable or malleablematerial and be placed over one or a plurality of teeth of a personduring the guided dental implantation surgery, the housing 20 a havingsides, wherein at least a portion of the sides are configured to flexunder stress, the sides configured to urge the flowable or malleablematerial against the teeth, and wherein the housing 20 a includes alocking mechanism 40 configured to reduce or eliminate a freedom ofmovement of the fixation tray by reducing or eliminating an ability ofthe at least the portion of the sides of the housing 20 a to flex understress. In some versions, the least a portion of the sides of thehousing are configured to flex such that a further a portion of thesides is from a top portion of housing the more that portion of thesides spreads outward under stress. In some versions, the system 10further comprises a registration element 60 configured to connect totray 20. In that case, system 10 includes that which is necessary forthe tray and lock 40 to be registered for purposes of the guidedsurgery. The registration element is configured to align for a computernavigation system used during the surgery the exact CT coordinates withthe exact real world coordinates of a registered body rigidly attachedto (or forming part of) system 10.

As seen from the flow chart of FIG. 16, one embodiment of the inventionis a method 100 of using a stable affixation system during dentalimplantation. Method 100 may comprise a step 110 of deploying a fixationtray 20 holding a flowable or malleable material over one or a pluralityof teeth, the fixation tray having a housing 20 a wherein at least aportion such as side portions of housing 20 a (in one implementationside walls (for example a first side wall 22 and a second side wall 24))are configured to flex under stress. There may also be a fixation traytop portion 26 configured to connect the first and second side walls.The housing 20 a defines a chamber 25 and may have any of the structuresdescribed with respect to any of the embodiments of fixation tray 20 orsystem 10. For example, housing 20 a may have an element such as extraflexible arm extensions, for example arm extensions that are inwardlyfacing (and that may be inclined) to urge the flowable or malleablematerial against the one or more teeth. For example, arm extensions 32,34 may extend from a free end or a point adjacent to a free end of, ormay extend from a different part of, each of the first and second sidewalls (or side portions of housing 20 a) as inclined inward-directed armextensions configured to urge the flowable or malleable material againstthe one or the plurality of teeth. In some embodiments, the step 110 ofdeploying may be accomplished rapidly and easily.

Method 100 may also include step 120 of locking the fixation tray suchas by a lock 40 or by deploying a locking wedge over the fixation tray,for example a locking wedge 40 that is configured to fixate tray 20 inplace or grip fixation tray 20 and/or reduce or eliminate its freedom ofmovement. The mechanism for reducing or removing the freedom of movementof tray 20 or fixating tray 20 in place may be any suitable mechanismfor example any mechanism described with regard to system 10 or tray 20.In some embodiments, the step 120 of locking effectuates a stable andsturdy system to which a tracking device may be attached and which isstable in the face of significant force applied from any of a variety ofangles and using leverage. Step 120 may also include locking an elementsuch as pole 65 for example by using a fastener or screw that traversesboth a hole in lock 40 and a hole in tray 20 (see FIG. 1, FIG. 5, FIG.9).

Step 130 of method 100 may comprise allowing the flowable or malleablematerial to harden, for example to harden into a rigid but crisp orbrittle state, for example a crisp or brittle state that is easilybreakable upon application of a force or stress such as shear stress.The flowable or malleable material in some case flows into spaces 21 inhousing 20 a of tray 20 so that when it hardens it locks into tray 20.The method 100 may include an additional step of performing the guideddental surgery while system 10, including tray 20 and lock 40, remain inplace in a sturdy and stable position without regard to forces exertedon system 10.

Step 140 may involve unlocking the lock 40 or removing the locking wedge40 and then removing the fixation tray 20, for example easily andrapidly with limited force without damaging the tooth or teeth. Forexample, the locking wedge 40 is removed in certain embodiments rapidlyby exerting a force on it for example using an instrument that isoperatively connected to the element in a cavity 62 of the fixation tray20. Removing the fixation tray 20 may be accomplished in certainembodiments by exerting a force that generates stress such as shearstress on the housing 20 a that may translate into stress such as shearstress on the crisp or brittle hardened material (formerly flowable ormalleable material). In one non-limiting implementation, this may beaccomplished by exerting a force (such as a rotational force) on anelement (such as a pole 65) of tray 20. For example the force may beapplied to an internal element of tray 20. In one implementation, theforce may be applied to an element situated in a cavity 62 of thefixation tray 20 such as in top portion 26 of tray 20 (which in someembodiments is a cavity 62 in a holder 28 of top portion 26) to generatepressure causing stress such as shear stress on portions of the tray 20and on the hardened material to break at least a portion of the hardenedmaterial (for example on an occlusal surface of the plurality of teeth),thereby allowing the sides or side portions of housing 20 a (includingarm extensions 32, 34 or including steps 23 a, 23 b) to flex anddislodge the fixation tray 20 from the plurality of teeth.

FIG. 1 is an exploded view that allows the visualization of the elementin the cavity 62 according to one embodiment. A tracking deviceconnector or handle 60 includes a pole portion 65 configured to fitinside cavity 62. In order to begin the process of removing the fixationtray 20, one can exert a rotational force on pole 65. This has theeffect of pressuring the entire fixation tray 20 but in particular onthe sides of tray 20, for example arm extensions 22, 24 of tray 20. Itmay have the effect of pressuring holder 28, top portion 26, side walls22, 24 and arm extensions 32, 34. It may have an additional effect ofexerting stress such as a shear stress and breaking at least a portionof the hardened material, for example on an occlusal surface of theplurality of teeth, thereby allowing side portions of housing 20 a toflex so as to dislodge fixation tray 20 from the one or the plurality ofteeth and remove fixation tray 20.

In method 100 (or method 200, 300, 400) if an element for example pole65, has been placed in tray 20, then step 140 may also include removinga fastener or screw that locks pole 65.

Another method 200 shown in FIG. 17 may comprise a step 210 of deployinga fixation tray holding a flowable or malleable material over one or aplurality of teeth, the fixation tray having at a least a portion suchas side walls configured to flex under stress, and a top portionconnecting them and having extra flexible arm extensions inward-facingto urge the flowable or malleable material against the one or moreteeth. For example, arm extensions 32, 34 may extend from a portion ofside walls 22, 24 (or side portions of housing 20 a) and in some casesfrom a free end, or from a point adjacent to a free end, of each of theside walls of the fixation tray 20, and the arm extensions 32, 34 may beinward-directed (and may be inclined) to urge the flowable or malleablematerial against the one or the plurality of teeth.

Step 220 of method 200 may comprise locking the fixation tray such as bydeploying a locking wedge 40 over the fixation tray 20, for example togrip the fixation tray 20, for example to limit a movement of the sidewalls of the fixation tray. Step 230 may involve allowing the flowableor malleable material to harden into a rigid state that is crisp orbrittle. The flowable or malleable material in some case flows intospaces 21 in housing 20 a of tray 20 so that when it hardens it locksinto the tray 20. Method 200 may include an additional step ofperforming the surgery while system 10, including tray 20 and lock 40,remain in place in a sturdy and stable position without regard to forcesexerted on system 10.

Step 240 may comprise unlocking the lock or removing the locking wedgeand then removing the fixation tray by exerting a force on an element ofthe fixation tray such as by rotating a pole or other element in acavity of the fixation tray such as its top portion 26, therebygenerating pressure against the housing 20 a which causes at leastportions of the housing 20 a to flex (the portions may be sides thatinclude arm extensions 32, 34) and which may causes breakage of thematerial, which allows dislodging the fixation tray from the pluralityof teeth.

A flow chart of another method 300 is shown in FIG. 18. It includes astep 310 of deploying a fixation tray holding a flowable or malleablematerial over one or a plurality of teeth, the fixation tray havingsomewhat side walls configured to urge the flowable or malleablematerial against the tooth or teeth for example using any mechanismdescribed above with respect to system 10 including for example eitherextra flexible inwardly facing arm extensions 32, 34 or using inwardlyfacing steps 23 a, 23 b. Locking the fixation tray using a lock on thetray or by deploying a locking wedge over the fixation tray may comprisea step 320 of method 300. Allowing the flowable or malleable material toharden is step 330. The flowable or malleable material in some caseflows into spaces 21 in housing 20 a of tray 20 so that when it hardensit locks into the tray 20. Method 300 may include an additional step ofperforming the surgery while system 10, including tray 20 and lock 40,remain in place in a sturdy and stable position without regard to forcesexerted on system 10. Step 340 may comprise unlocking the lock such asby removing the locking wedge and then removing the fixation tray byexerting a force on an element in a cavity of the fixation tray so as tobreak the hardened material.

Method 400 may comprise a step 410 of deploying a fixation tray holdinga flowable or malleable material over one or more teeth, the fixationtray 20 having a housing 20 a defining a chamber 25 and having amechanism to urge the material against the one or more teeth. Step 420may comprise locking the fixation tray 20 to reduce or eliminate itsfreedom of movement. Step 430 may comprise allowing the material toharden and performing the guided surgery while the tray 20 and lock 40remain in place in a sturdy and stable position. Step 440 may compriseremoving or unlocking the lock 40 and then removing the fixation tray20. Any suitable version of any of the elements described herein forsystem 10 may be used for that element in method 400.

By using a tray 20 in any of methods 100, 200, 300, 400 or system 10having at least a portion configured to flex under stress, the system 10is designed to break the hardened material when pressure is exerted forexample by rotating an element such as pole 65 in cavity 62 of topportion 26 of tray 20. As a result of the tray 20 having a portion orportions configured to flex under stress exerted on the fixation tray 20results in pressure being exerted against the hardened (previouslyflowable or malleable) material. This breaks the hardened material andthis hardened material comes off the teeth when the fixation tray 20 isdislodged. If the tray 20 were rigid it may simply take out the wholetooth or teeth. Since for stability reasons, system 10 fills an undercutof the plurality of teeth, there is no option to realistically just pullsystem straight up vertically.

As noted, connector 60 can be connected to or can itself be aregistration body used in mating the CT coordinates and the real worldcoordinates for the guided dental surgery. Accordingly, in an embodimentof the invention, method 500 of registration includes a step ofperforming a computed tomography (CT) scan of the patient's teethwithout the system 10 being attached to the teeth. Step 520 comprisesdeploying any version of system 10 over one or a plurality of teeth(including tray 20 holding flowable or malleable material and includinglock 40) so that system 10 is firmly attached to the one or a pluralityof teeth and such that a connector 60 is also rigidly attached to system10 such as by rigid attachment to tray 20 of system 10 (connector 60 istypically outside or mostly outside the patient's mouth). Step 530involves performing registration by taking a tracking device (used inconjunction with the guided dental surgery) and touching it along theone or plurality of teeth.

In another embodiment of the invention, method 600 of registrationincludes a step 610 of deploying any version of system 10 over one or aplurality of teeth (including tray 20 holding flowable or malleablematerial and including lock 40) so that system 10 is firmly attached tothe one or a plurality of teeth and doing so such that connector 60 isalso rigidly attached to system 10 such as by rigid attachment to tray20 of system 10 (connector 60 is typically outside or mostly outside thepatient's mouth). Step 620 comprises performing a computed tomography(CT) scan of the one or the plurality of the patient's teeth afterdeployment of the tray 20 and lock 40 and connector 60. Step 630comprises performing registration by taking the tracking device (used inconjunction with the guided dental surgery) and either (i) touching italong points of the connector 60 to register the connector 60 or (ii)simply rigidly attaching it (the tracking device) to the connector 60 toregister the connector 60 since the dental surgery navigation system'ssoftware deduces the coordinates of the connector 60 from thecoordinates of the tracking device to which it is rigidly attached.

These two versions of the registration process (500, 600) can also becombined with any or all of the steps of methods 100, 200, 300, 400. Assuch, the step of removing the lock and tray (and/or allowing thematerial to harden) can be omitted from the list of steps of theregistration method in some versions.

In one embodiment of the invention, a stable affixation system forguided dental implantation, comprises a fixation tray 20 having ahousing 20 a that defines a chamber 25 configured to house a flowable ormalleable material and be placed over one or a plurality of teeth of aperson during guided dental implantation surgery, the flowable ormalleable material configured to harden into a crisp or brittle materialso as to conform to a contour of the one or the plurality of teeth, thehousing having a mechanism configured to urge the flowable or malleablematerial (and/or when it is already hardened) toward the one or theplurality of teeth. The system 10 also comprises a lock 40 or lockingwedge 40 configured to lock tray 20 or be positioned on or over thefixation tray 20 so as to reduce or eliminate a freedom of movement ofhousing 20 a. Housing 20 a may include a mechanism configured to jointhe flowable or malleable material, once hardened, to housing 20 a suchthat a greater separation force is required to separate the flowable ormalleable material, once hardened, from the housing, than a separationforce required to separate the flowable or malleable material from theone or the plurality of teeth.

The housing 20 a may include a portion configured to flex upon stress.For example, housing 20 a may have one or more recesses (as describedabove) and in some versions, locking wedge may include one or morecorresponding projecting members. In some versions, locking wedge 40includes a first locking wedge side wall 42 thicker than a first sidewall 22 of housing 20 a and a second locking wedge side wall 44 thickerthan a second side wall 24 of housing 20 a.

Housing may have sides at least a portion of which are configured toflex under stress. For example, sides 22, 24 may flex outwardly understress. For example, free ends of sides 22, 24 may spread outwardlyunder stress. In some case, the further a portion of sides 22, 24 isfrom a top portion 26 of housing 20 a, the more that portion of thesides spreads outwardly under stress (for example due to a clamping orholding force at or near the top portion 26 of housing 20 a).

In some embodiments, housing 20 a has a mechanism configured to hold atleast part of a tracking element and a mechanism configured to exert aforce or a stress such as shear stress on the housing and/or on thecrisp or brittle material so as to break at least a portion of the crispor brittle material and dislodge the fixation tray from the one or theplurality of teeth. When the force is applied, the portion or portionsof housing 20 a configured to flex may then flex making it easier tocause stress on the hardened material and easily dislodge tray 20.

For example, the force may be applied from inside of tray 20. In oneimplementation, housing 20 a has a cavity 62 configured to receive atracking element or a handle of a tracking element. Cavity 62 may alsobe configured to receive an element (such as a pole 65 of a connector 60of the tracking device) configured to exert a force or stress such asshear stress on the housing 20 a (or a portion of housing 20 a or onside walls of housing 20 a) and/or on the hardened material so as tobreak at least a portion of brittle material and thereby dislodge thefixation tray 20 from the one or the plurality of teeth.

The mechanism for customizing the system 10 to the individual patient'steeth in order to facilitate rapid placement of the system 10 may beimplemented, as seen in FIG. 15, in certain embodiments, by customizingthe housing to the individual patient's teeth. This is implemented insome cases by the flowable or malleable material and by providinghousing 20 a of fixation tray 20 with a pair of inwardly directed armextensions 22, 24 or inwardly directed steps 23 a, 23 b configured tourge the flowable or malleable material against the one or the pluralityof teeth (including after such material hardens into a rigid state).

While the invention has been described with respect to a limited numberof embodiments, it will be appreciated that many variations,modifications and other applications of the invention may be made.Therefore, the claimed invention as recited in the claims that follow isnot limited to the embodiments described herein.

What is claimed is:
 1. A stable affixation system for guided dentalimplantation, comprising: a fixation tray customizable to the patientincluding a housing that defines a chamber configured to house aflowable or malleable material and be placed over a top, front and rearof one or a plurality of teeth of a person, the one or the pluralityoccupying a portion of the person's row of teeth, during the guideddental implantation surgery, the housing having sides, at least aportion of the sides are configured to flex under stress, the sidesconfigured to urge the flowable or malleable material against the teeth;and a lock positioned on the fixation tray so as to reduce or eliminatea freedom of movement of the fixation tray, wherein each of the sidewalls of the housing has a free end configured to fit closer to agumline of each jaw of the person than an opposite end, wherein in atleast one position of the system the free ends are configured to flexoutward when subjected to a squeezing force at the opposite ends.
 2. Theaffixation system of claim 1, wherein the fixation tray is configured tobe placed over the plurality of teeth and wherein the chamber defined bythe housing comprises a channel that is substantially straight along adirection of the row of teeth.
 3. The affixation system of claim 1,wherein the lock has an inner surface configured to define a chamberinto which at least a portion of the fixation tray is configured to fiteither snugly or using a friction fit.
 4. The affixation system of claim1, wherein the lock includes a mechanism for fixating at least sideportions of the housing rigidly in place.
 5. The affixation system ofclaim 1, wherein the housing includes a structure configured to join theflowable or malleable material, once hardened, to the housing such thata greater separation force is required to separate the flowable ormalleable material, once hardened, from the housing, than a separationforce required to separate the flowable or malleable material from theone or the plurality of teeth.
 6. The affixation system of claim 1,wherein the lock is configured to reduce a freedom of motion of each ofa first side wall and of a second side wall of the fixation tray.
 7. Theaffixation system of claim 1, wherein the housing comprises a pair ofinclined, inwardly directed arm extensions that extend from an innersurface of the chamber.
 8. The affixation system of claim 7, wherein thehousing is made from a first material and the arm extensions are made ofa second material that is flexible.
 9. The affixation system of claim 1,wherein the lock has a first wall or projecting member configured toextend alongside one of the side walls of the housing and a second wallor projecting member configured to extend alongside a second of the sidewalls of the housing.
 10. The affixation system of claim 1, wherein thefixation tray has recesses and the lock has corresponding projectingmembers.
 11. The affixation system of claim 10, wherein the projectingmembers project from an inner surface of a top portion of the lock. 12.The affixation system of claim 10, wherein the recesses aresubstantially planar recesses situated such that when the projectingmembers mate with the substantially planar recesses, a firstsubstantially planar projecting member adjacent to and inward of a firstside wall of the fixation tray and a second substantially planarprojecting member adjacent to and inward of a second side wall of thefixation tray.
 13. The affixation system of claim 1, wherein the housinghas an elongated cavity configured to receive a tracking element. 14.The affixation system of claim 1, wherein an end view of at least one of(i) the fixation tray or (ii) the lock is substantially U-shaped. 15.The affixation system of claim 1, wherein the housing includes armextensions that are each configured to urge the flowable or malleablematerial to harden in an undercut of the one or the plurality of teethto stabilize the system.
 16. The affixation system of claim 1, whereinthe fixation tray includes side walls and arm extensions and each of thearm extensions is more flexible than each of the side walls.
 17. Theaffixation system of claim 1, wherein the housing has spaces configuredto allow the flowable or malleable material to flow into and, oncehardened, to lock into.
 18. A stable affixation system for guided dentalimplantation, comprising: a fixation tray having a housing that definesa chamber configured to house a flowable or malleable material and beplaced over a top, front and rear of one or a plurality of teeth of aperson, the one or the plurality occupying a portion of the person's rowof teeth, during the guided dental implantation surgery, the flowable ormalleable material configured to harden into a crisp or brittle materialso as to conform to a contour of the one or the plurality of teeth, thehousing having a mechanism configured to urge the flowable or malleablematerial toward the one or the plurality of teeth; and a lock positionedover the fixation tray snugly or using a friction fit and so as toreduce or eliminate a freedom of movement of the fixation tray, the lockhaving a first lock side wall that extends alongside one of the sidewalls of the housing and a second lock side wall that extends alongsidea second of the side walls of the housing, wherein each of the sidewalls of the housing has a free end configured to fit closer to agumline of each jaw of the person than an opposite end, wherein in atleast one position of the system the free ends are configured to flexoutward when subjected to a squeezing force at the opposite ends. 19.The affixation system of claim 18, wherein the housing includes amechanism configured to join the flowable or malleable material, oncehardened, to the housing such that a greater separation force isrequired to separate the flowable or malleable material, once hardened,from the housing, than a separation force required to separate theflowable or malleable material from the one or the plurality of teeth.20. The affixation system of claim 18, wherein the housing has amechanism configured to hold at least part of a tracking element and amechanism configured to exert stress on the housing and/or on the crispor brittle material so as to break at least a portion of the crisp orbrittle material and dislodge the fixation tray from the one or theplurality of teeth.
 21. The affixation system of claim 18, wherein thefixation tray is configured to be placed over the plurality of teeth andwherein the chamber comprises a channel that is substantially straightin a direction along the row of teeth.
 22. A stable affixation systemfor guided dental implantation, comprising: a fixation tray customizableto the patient including a housing that defines a chamber configured tohouse a flowable or malleable material and be placed over a top, frontand rear of one or a plurality of teeth of a person, the one or theplurality occupying a portion of the person's row of teeth, during theguided dental implantation surgery, the housing having side walls, atleast a portion of the side walls are configured to flex under stress,the side walls configured to urge the flowable or malleable materialagainst the teeth, wherein the housing includes a locking mechanismconfigured to reduce or eliminate a freedom of movement of the fixationtray by reducing or eliminating an ability of the at least the portionof the sides of the housing to flex under stress, wherein each of theside walls of the housing has a free end configured to fit closer to agumline of each jaw of the person than an opposite end, wherein in atleast one position of the system the free ends are configured to flexoutward when subjected to a squeezing force at the opposite ends. 23.The affixation system of claim 22, wherein the at least a portion of thesides of the housing are configured to flex such that the further thatthe at least a portion of the sides of the housing is situated from atop portion of the housing, the more the at least a portion of the sidesof the housing is configured to spread outward under stress.
 24. Theaffixation system of claim 22, further comprising a registration elementconfigured to be rigidly attached to the tray.